Hank, I'm not that knowledgeable on DirecTV components. However, I did a quick search on the internet and from what I can find the last number indicates the manufacturer. I didn't know it, but evidently DirecTV has the same receiver manufactured by a variety of companies. The statement is that "They give the manufacturers a set of specifications and they make the units."'
Here is one list that I located that is supposed to be the manufacturer code:
-100 Thomson
-200 Samsung
-300 Philips
-400 Hughes
-500 Humax
-600 LG
-700 Pace
-800 NEC
I don't know whether you checked with Winegard? That's where I bought my HR24--but I don't see one listed on their site now (they list the H24). They were helpful in consulting and providing advice on my setup when I contacted them. Another company which sells receivers and provides consultations is Solid Signal. I've never talked with them, but they have a reputation as being knowledgeable and helpful. They currently have HR24s listed as available. They offer a phone number to consult with their "DirecTV Experts".
Mike
